Photoactivable Multimodal Antimicrobial Nanoconstructs

126 Pages·2017·11.43 MB·English

U D S
NIVERSITÁ EGLI TUDI DI
C
ATANIA
International PhD in Chemical Sciences (XXX cycle)
Photoactivable Multimodal
Antimicrobial Nanoconstructs
Author: Supervisor:
Marta PÉREZ-LLORET Prof. Salvatore SORTINO
ii
Athesissubmittedinfulfillmentoftherequirements
forthedegreeofDoctorofPhilosophy
inthe
LaboratoryofPhotochemistry
DepartmentofDrugSciences
iii
Declaration of Authorship
I,MartaPÉREZ-LLORET,declarethatthisthesistitled,“PhotoactivableMultimodalAntimi-
crobialNanoconstructs”andtheworkpresentedinitaremyown. Iconfirmthat:
• This work was done wholly or mainly while in candidature for a research degree at
thisUniversity.
• Whereanypartofthisthesishaspreviouslybeensubmittedforadegreeoranyother
qualificationatthisUniversityoranyotherinstitution,thishasbeenclearlystated.
• WhereIhaveconsultedthepublishedworkofothers,thisisalwaysclearlyattributed.
• Where I have quoted from the work of others, the source is always given. With the
exceptionofsuchquotations,thisthesisisentirelymyownwork.
• Ihaveacknowledgedallmainsourcesofhelp.
• Where the thesis is based on work done by myself jointly with others, I have made
clearexactlywhatwasdonebyothersandwhatIhavecontributedmyself.
Signed:
Date:

v
“Preventionisbetterthancure.”
DesideriusErasmus(1466–1536)

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UniversitáDegliStudidiCatania
Abstract
DepartmentofDrugSciences
DoctorofPhilosophy
PhotoactivableMultimodalAntimicrobialNanoconstructs
byMartaPÉREZ-LLORET
The search of novel antibacterial treatment modalities designed to face problems of an-
tibioticMultiDrugResistance(MDR)associatedwiththealarminglylowturnoverofnew
clinically approved antibiotic drugs is one of the main challenges in biomedicine. In this
frame,theachievementoftailoredsystemsabletoreleasetherapeuticagentsinacontrolled
fashionisoneofthegrowingareaintheburgeoningfieldofnanomedicine.Lightrepresents
the most elegant and non-invasive trigger to deliver bio-active compounds on demand at
thetargetsitewithsuperbcontrolofthreemainfactors,site,timinganddosage,determin-
ing for the therapeutic outcome. In addition, light triggering is biofriendly, provides fast
reaction rates and offers the great benefit of not affecting physiological parameters such
astemperature, pHandionicstrength, fundamentalrequisiteforbiomedicalapplications.
Recentbreakthroughsofnanotechnologyoffertheopportunitytocharacterize,manipulate
and organize matter at the nanometer scale, controlling the size and shape of the result-
ingnanomaterialsandgreatlyimprovingthebiocompatibilityandthecellularuptakeeffi-
ciency. This thesis focuses on the design and fabrication of light-activated nanoconstructs
for the controlled delivery of “unconventional” therapeutics such as reactive oxygen and
nitrogen species, and heat which, in contrast to “conventional” drugs, do not suffer MDR
problems and display reduced systemic effects. A range of nanosystems able to generate
individually,sequentiallyorsimultaneouslytheabovecytotoxicagentsisreportedand,in
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somecase,theirantibacterialactivityisalsoinvestigated.Thisdissertationisdividedintwo
sections: thefirstoneregardsnanomaterials,whilethesecondfocusesonmolecularhybrid
systems,allprecededbyabriefin-troduction.
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Contents
DeclarationofAuthorship iii
Abstract vii
1 Introduction 1
1.1 IntroductiontothePhDdissertation . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 MultiDrugResistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 Nanotechnologyinmedicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4 Lightbasedstrategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4.1 PhotodynamicTherapy . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4.2 NitricOxide-basedtherapy . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.4.3 PhotothermalTherapy . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.5 Nanomaterials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.5.1 MetallicNanoparticles . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
SilverNanoparticles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
GoldNanoparticles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.5.2 Grapheneoxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.6 Molecularhybridsbasedon: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.6.1 Cyclodextrins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.6.2 Polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.7 Multimodaltherapy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
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I NanoMaterials 23
2 Metallicnanoparticles-basedmaterials 25
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2.2 Experimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.2.1 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.3 Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.3.1 Photochemicalexperiments . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.3.2 Laserflashphotolysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.3.3 Photothermalexperiments . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.3.4 Antibacterialtests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
MICforsilverparticles. . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Time-Dose-Effectcurvesforsilverparticles . . . . . . . . . . . . . . . . 29
2.4 ResultsandDiscussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.4.1 Dextran-benzophenonecharacterisation . . . . . . . . . . . . . . . . . . 29
2.4.2 SynthesisofNPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
SilverNPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Core-ShellAuAgNPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.4.3 Photothermaleffect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
2.4.4 Antibacterialresults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
MICforsilvernanoparticles . . . . . . . . . . . . . . . . . . . . . . . . . 38
Time-Dose-Effectcurvesforsilverparticles . . . . . . . . . . . . . . . . 39
2.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
3 Grapheneoxide 43
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
3.2 Resultsanddiscussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
3.3 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
3.4 ExperimentaSectionl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54